Herpes simplex virus type 1 infection increases the carbohydrate binding activity and the secretion of cellular galectin-3

Galectin-3 binds beta-galactoside-containing sugars and is a chemoattractant for monocytes, macrophages, and neutrophils. Galectin-3 was identified by mass spectrometry from an anti-gI affinity column; however, we determined that galectin-3 did not bind gI, but rather that HSV-1 infection increased galectin-3 binding to carbohydrate residues on IgG. Our conclusions are based on the following observations: (1) galectin-3 from cells infected with a gI-deleted HSV-1 mutant virus bound anti-gI IgG; (2) galectin-3 from wild-type HSV-1 infected cells bound nonimmune IgG; (3) more galectin-3 from infected than uninfected cells bound IgG; and (4) binding to IgG was blocked by lactose, a competitive inhibitor of galectin-3 carbohydrate binding. HSV-1 infection did not increase galectin-3 expression, but did increase its secretion. We propose that increased carbohydrate binding and secretion of galectin-3 contribute to an early pro-inflammatory innate immune response to HSV-1 infection.